Multitone whistle



s- 8, 1950 w. R. SMITH 2,518,435

MULTITONE WHISTLE Filed May 14, 1949 ig? INVENTOR ATTORNEY Patented Aug. 8, 1950 MULTITONE WHISTLE William R. Smith, Philadelphia, Pa., assignor to The A. 0. Gilbert Company, New Haven, Conn, a corporation of Maryland Application May 14, 1949, Serial N 0. 93,380

9 Claims.

This invention relates to whistles and particularly to multi-toned whistles of miniature size for incorporation in the extremely limited spaces available in the smallest gauges of toy railway trains or rolling stock, and in tiny trackside toy buildings.

It has been proposed to provide multi-toned whistles operated by split streams of air generated by the same motor-driven air impeller, but the problem of condensing into a much more tiny space than heretofore a resonance chamber having suflicient air volume to produce deep and low-pitched tones such as will efiectively imitate the actual noise of a distant train whistle, has presented problems more acute than those of reducing the size of the air impeller and its motor which generate the sound producing streams of air. Heretofore production of plural whistle tones has been accomplished by making one resonance chamber greater in straight length than a companion resonance chamber. This has required a greater maximum overall dimension of the sound box than has been available in toy trains of the very miniature sizes such as the so-called HO gauge.

It is an object of thi invention to provide a miniature whistle of satisfactorily loud and low pitched tone having at least one. and preferably a plurality of, resonance compartments of such construction, shape and relationship that the aggregate size of a chamber divided into such plural compartments may be compacted into overall proportions whose maximum dimension in the direction of its greatest length is smaller than has heretofore been possible.

A relatedobject is to differentiate the tone and pitch produced by companion resonance compartments by variationin the width, rather'than in the length, of the compartments.

Another object is toproduce a resonance chamber of effective elongation in tortuous form with-' out the use of tubing structure.

Still another objectis to integrate lural resonance chambers into a comparted sound box having the above characteristics constructed substantially throughout of substantially fiat-walls and partitions thereby to facilitate its casting from metal. 7

Means for attaining the above and related objectives of the invention will appear in the following description of a successful embodiment thereof, which description has reference to the appended drawings wherein:

Fig. 1 is a side view of a motor-driven rotary air impeller mechanically associated with a miniature sound box embodying the present invention and drawn on a considerably larger scale than the preferred actual size, portions thereof being broken away or shown in section on a central vertical plane to expose the construction Fig. 2 is an isometric view of the sound box drawn on a still larger scale with some of its exterior walls and interior partitions removed or partially broken away better to reveal the construction.

Fig. 3 is a fragmentary View of a portion of the structure shown in Fig. 2 with certainwalls and webs of the sound box still further broken away to exhibit certain features of the air flow.

Figs. 4, 5, 6, and 7 are, respectively, views taken in section onthe planes 4-4, 5-5, 6-6, and 'l'|, in Fig. 1, looking in the direction of the arrows.

In Figs. 1 and 4 my improved sound box designated l2 as a whole is shown removably assembled to and supported solely on a frame bracket I3 which may be integral with or a rigid part of the body of a toy railway locomotive or other hollow piece ofrolling stock (not shown) or contained in toy building structure such as a tiny trackside power plant in whose restricted space limits the sound box must be contained and concealed. Also rigid with frame bracket, I3 is a bearing bracket I4 in which is journaled one end of the shaft ii of a motor I6, the other end of shaft l5 being journaled in a bearing cup l9 lodged in upright wall 25 of the sound box I2, which cup is coaxial with the shaft bearing in bracket l4. Motor shaft l5 carries an air impeller 29 fixed thereon by press fit over the knurled shaft por-. tion 2| for rapid rotation in the blower cavity 22. Cavity 22 as best shown in Fig. 4 is of snail shape and is bordered by the upright wall 25 of the sound box.

Sound box l2 may be cast of metal in a shape to have the top wall 26, the end wall 21 and bottom wall 28, all integral and continuou with one another and with, the upright wall 25. The remaining walls. 3! which surround blower cavity 22 may also be integral or continuous with upright wall 25 and are provided with threaded. holes 32 receiving the screws 33 which fasten the sound box [2 to bearing bracket I3 in a manner to derive its sole support from the latter. Other threaded holes 34 in the sound box casting receive screws 35 which serve to fasten side plates According to the present invention, and for the purpose of producing a sound box of sufiicient volumetric capacity to afford effective resonance and whose maximum dimension in the direction of its greatest length shall be smaller than has heretofore been possible, the interior of the sound chamber closure is comparted. by a system of partitions and/r web walls shaped and arranged to attain the indicated novel result. There is an upright partition wall 46 shaped and arranged in the sound chamber space to divide the latter into side-by-side separated resonance compartments 4i and 42, so that the former is wider than the latter. In resonance compartment 4.I there are two mainly fiat web walls 43 and 44 in spaced planes. In resonance compartment 42 there are two similar web walls 45 and 4t substantially'coplanar with walls 43 and 44, respectively. The Web walls on a common side of partition wall 4!] have free edges 41 spaced from respectively opposite walls 25 and 2'! of the sound chamber closure. Thus each of the resonance compartments is converted to a tortuous shape. some 0'. the advantages of this invention might be obtained if only one web wall were to be incorporated internally of one or both of the resonance chambers. One such web wall could serve to convert at least a portion of the interior of the resonance chamber to the shape of a return bend.

By any or all of the expedients above disclosed there is produced a greater tone deepening effective len th of resonance chamber giving a more satisfactory amplification of sound realistically like the whistle of a distant train or industrial arrows in Fig. 3 through separate tapering blow orifices 5i and 52 toward the separate bodies of air trapped in. both resonance chambers 4:!

and 42." The former gives from channel 59,

toward the relatively wider resonance compartment 4| while the latter gives from the same channel toward the relatively narrower resonance compartment 42.. Directly adjacent the elongatedblow orifices 5i and 52 respectively there are correspondingly elongated outlets '53 and, 54 in base wall 28 constructed and located to afiford outlet for the separate streams of air passing through blow orifices 5! and'52 to the exterior of the sound box. Such streams of air are in reactive fluid communication with the resonating air confined in compartments 4! and 42. As is well known in whistle construction, the edge 55 of each of the outlets 53 and 54 is pref erably sharpened to a wedge shape in .orderto, cleave and vibrate the outflowing'streams "of air. As will be clear from Figs. 5 and 6, blow orifices 5i and 52, as well as the outlets '53 and 54,are

pneumatically isolated from each other by the intervening partition wall 40.

It has been found that the resonating action of the body 01' air trapped in compartments 4! and 42 is improved in distant train whistle 'imitating effect if generous fillets are provided at the interior corners formed by the wall and/or partition junctions which define the tortuous length of the compartments as indicated at 56 in Figs. 1 and 2. His assumed that this reduces eddy cmrents and gives more freedom to the wave surges of the resonance action.

Having thus described but bne illustrative embodiment of these new principles in multi-tone sound box construction wherein a difference in tone is produced by diiference in the lateral cross-sectional size, rather than the tortuous length, of plural cooperative resonance compartments, the appended claims are directed to and intended to cover all variations and substitutes for the particular parts, shapes and arrangements herein pictured and described as come within the most inclusive fair means of their definitions.

Iclaim:

L. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, walls forming a box-like closure confin ing achamber space for trapping a volume of resonating air, at least one blow'orifice shaped and disposed to direct a stream of Whistle-pro ducing air toward and into fluidcommunication with space-trapped Volume of air, at. least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior at said chamber space, and a partition wall in said chamber space shaped and arranged.- to; divide the latter into pneumatically separate air-resonating compartments of respecti ely diflering volumetric capacity, at least one of said com partments having a tortuous shape whereby relatively long and narrow pro ortions are in"? parted thereto for producing whistle noises oi lower tone.

2. In. a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, Walls forming a box-like closure confining a chamber s ace for trapping a volume of resonating air, at least one blow orifice sl'iaped and disposed to direct a stream of whietle-pro clucing air toward and into fluid communicati x -i with said space trapped volume of air, at. least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively differing volumetric capacity and substantially similar tortuous shapes having similar eiTective resonating lengths, said partition wall being situated'to cause said compartments to difier in width sufficiently tocausea diiierence in pitch of the whistle tones produced thereby.

- 3. In a whistle for containment within the tiny interior of miniature'hollow toys, a comparted blow orifice shaped and disposed to permit said into pneumatically separate air-resonating com- "partments of respectively "dififering volumetric capacity, andat least-o'i'ieweb wallinside of at least one of said compartments shaped and arranged to convert at least a portion of the com partment into a tortuous shape having a return bend whereby relatively long and narrow proportions are imparted to the-compartment'ior producing whistle tones of loweredpitch. i

4. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, walls forming a box-like closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistle-producing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively differing volumetric capacity, and web walls inside of said compartments in coplanar alignment while located on respectively opposite sides of said partition wall, said web walls being shaped and arranged to convert each of said compartments into a tortuous shape whereby relatively long and narrow proportions are imparted thereto for producing whistle tones of lowered pitch.

5. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, walls forming a box-like closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistleproducing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively differing volumetric capacity, and a plurality of web walls inside of at least one of said compartments shaped and arranged to convert the compartment into a tortuous shape imparting relatively long and narrow proportions thereto for producing whistle tones of lowered pitch.

6. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber com rising in combination, walls forming a box-like closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistle-producing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior 01 said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively difiering volumetric capacity, and a plurality of web walls inside 01' at least one of said compartments located in spaced planes each having a free edge spaced from respectively opposite walls of said closure in a manner to convert the compartment into a tortuous shape imparting relatively long and narrow proportions theretov for producing whistle tones of lowered pitch. f f l 7. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in com bination, walls forming a box-dike closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistle-protlucing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to escape to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively differing volumetric capacity, and a plurality of mainly fiat web walls inside of at least one of said compartments located in spaced planes each having a free edge spaced from respectively opposite walls of said closure in a manner to convert the compartment into a tortuous shape imparting relatively long and narrow proportions thereto for producing whistle tones of lower d pitch.

8. In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, walls forming a box-like closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistle-producing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to esca e to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-resonating compartments of respectively differing volumetric capacity, and a plurality of mainly flat web walls on each side of and joined to said partition wall, the web walls on opposite sides of said partition wall being in substantially planar alignment and the web walls on each common side of said partition wall bein located in spaced planes thereby to convert the compartments into tortuous shapes imparting relatively long and narrow roportions thereto for producing whistle tones of lowered pitch.

9, In a whistle for containment within the tiny interior of miniature hollow toys, a comparted multi-tone sound chamber comprising in combination, walls forming a box-like closure confining a chamber space for trapping a volume of resonating air, at least one blow orifice shaped and disposed to direct a stream of whistle-producing air toward and into fluid communication with said space-trapped volume of air, at least one air outlet in one of said closure walls close to said blow orifice shaped and disposed to permit said stream of air to esca e to the exterior of said chamber space, a partition wall in said chamber space shaped and arranged to divide the latter into pneumatically separate air-reso nating compartments of respectively differing volumetric capacity, and a plurality of mainly fiat web walls on each side of and joined to said partition wall, the web walls on opposite sides of said partition wall being in substantially planar alignment and the web walls in each common side of said partition wall being located in spaced planes, each of the last said web walls having a 'fi edge spaced from a wallrof said closure in a manner to convert each (if said ccmpartments int? a 'tar'tuous shape "imparting 'r'latively' long and narrow proportions thereto far producing whistle toms of lowered pitch. x

v v v WmuAM R. SMITH.

REFERENCES CITED Thenfyl lowing references are of record in the tile of this patent;

8 ,7 UNITED STATES 'xw yrmq's' Number Date Name Broden -9.-- Nov. 5, 1935 Hall --.1- m. Apr; 6, 1937 Schumacher July 12, 1938 Gia'imo M. Jan. 10, 1939 

